Fluorescein angiographic evaluation of the effect of latanoprost treatment on blood-retinal barrier integrity: A review of studies conducted on pseudophakic glaucoma patients and on phakic and aphakic monkeys

Endogenous prostaglandins (PGs) have been claimed to play a role in the development of cystoid macular edema (CME). Two fluorescein angiographic studies evaluating the effect of latanoprost, a new ocular hypotensive PG analogue, on blood-retinal barrier integrity are, therefore, reviewed here. In the first study, six of eight unilaterally aphakic cynomolgus monkeys were treated bilaterally once daily for six months with 0.035% latanoprost (seven times the clinically used oculohypotensive concentration). Two of the animals served as controls. Fluorescein angiography of the fundus after one, three and six months of treatment revealed no leakage of fluorescein in any of the 16 eyes. In another study, pseudophakic eyes of 16 glaucoma patients who received twice-daily treatment with 0.006% latanoprost for four weeks were compared to eight patients treated with placebo. Biomicroscopic examination did not reveal any signs of CME and only one placebo-treated eye revealed a slight perifoveal leakage of fluorescein. These studies suggest that topically-applied latanoprost does not have a fluorescein angiographically detectable direct effect on the integrity of the blood-retinal barrier system in phakic or aphakic monkey eyes or in pseudophakic human eyes. This does not rule out the occurrence of CME in eyes more susceptible to CME, due to vitreous loss, posterior capsulotomy, or other postoperative situations. Especially in those eyes a study with latanoprost is proposed. Since, fluorescein angiography is a rather crude method of detecting abnormalities of the blood-retinal barriers, vitreous fluorometry in addition is suggested.